1. Field of the Invention
This invention relates to a method and system for controlling the operation of movable wireless networks for operation in multiple network environments.
2. Description of Related Art
Currently, non-stationary or movable wireless network systems exist that are based within movable objects, such as ships, trains, aircraft, buses, and the like. Accordingly, as the movable object moves, so does a coverage area of the movable wireless network.
As a result of their changeable position, movable wireless networks can come into contact with stationary or other movable wireless networks. For example, the coverage area of the movable wireless network may overlap with the coverage area of a stationary network. When such an event happens, the respective wireless networks can undesirably interfere with each other, and thus result in interrupted service to their respective wireless network users. For example, the movable wireless network of a cruise ship may come into contact with a land-based stationary wireless network when the ship pulls into a port, or simply comes within close proximity to land. Since resources, such as transmitter power and frequency are subject to local and international rules, laws and agreements, the use of the movable wireless network can be restricted. Accordingly, when this event occurs, the movable wireless network can be shutdown to avoid potential interference between the movable and stationary wireless networks, as well as violation of any local rules or regulations, and the movable wireless network users aboard the ship would then switch from the movable wireless network to communicate through the land-based stationary wireless network.
One technique of avoiding interference between a movable wireless network and stationary wireless network is described in PCT publication WO 01/15338. The WO 01/15338 publication teaches that an operator of a movable wireless station will generally not have a license to operate within the territory covered by a fixed base station, and may only be permitted to operate in international waters. Accordingly, the system taught in WO 01/15338 includes a movable base station that is capable of detecting whether the movable base station is within the range of a fixed base station, such as a land-based stationary wireless network. In order to avoid interference with the fixed base station, when the movable wireless base station detects that it is within a particular range of a fixed base station, the movable wireless base station is shut down or the power of the movable wireless base station is reduced. This has the effect of avoiding interference between the wireless networks by having the movable wireless network defer to the fixed network whenever the movable wireless network determines that it is within a particular range of the fixed base station.